Quad-polarized SAR measurements of ocean currents in C- and L-bands

Abstract

In this study we exploit the polarization sensitivity of high-resolution SAR measurements in C- and L-bands using a methodology suggested in [1, 2] to study the physics of radar imaging of upper ocean dynamics. Using samples of RADARSAT-2, ALOS PALSAR and ALOS-2 PALSAR-2 quad-polarization ocean SAR scenes, we decompose dual co-polarized (VV and HH) radar data into polarization difference (PD) and non-polarized (NP) components. Following [1, 2] these quantities provide means to distinguish Bragg scattering and non-polarized radar returns related to the quasi-specular reflection from breaking waves and from slopes of “regular” large-scale waves, and assess their relative role in the formation of surface current signatures in C- and L-band SAR ocean images. While C-band SAR features of ocean currents are fully dominated by non-resonant and non-polarized radar scattering from breaking waves, their manifestation in L-band SAR images are formed by Bragg waves, wave breaking and large-scale “regular” waves modulations by the currents.